Could you explain what the "gas" issue or direct me to the thread.
Chlorine gas is toxic and can be fatal.
If I remember correctly:
In low concentrations, it is an irritant to the tongue and throat, and can settle in the lungs, combine with moisture there, and form hydrochloric acid. At elevated concentrations, it can kill or severely damage tissue within just a few breaths.
It was used in World War I as a poison gas, and I believe there have been some terrorist-type attacks which utilized chlorine.